If you believe you are experiencing appendicitis pain, please call your doctor immediately. If s/he is not available, a visit to the ER. Vomiting with appendicitis is usually due to an emergency situation, so you don't want to wait until that happens. Be well.
Another possibility is diverticulitis, which would be more common in somebody in late 40s or older. I don't see your age on your profile. Diverticulitis is often linked to constipation.
Yes you could have a problem with your appendix. The symtoms vary. Pain goes down as you age as well. I would get it checked by your doctor. They can sometimes tell by a couple of blood tests and palpating the area.